Revenues (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) unit	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Disaggregation of Revenue [Line Items]
Revenue, Performance Obligation, Payment Terms	20 days
Cost of services	$ 57,912	$ 53,171	$ 56,909
Retroactive water revenues impact as a result of a proposed decision	30,000
GSWC
Disaggregation of Revenue [Line Items]
Revenue impact due to lower cost of debt	$ 6,400
Golden State Water Company and Bear Valley Electric Service, Inc.
Disaggregation of Revenue [Line Items]
Period within which Expected Additional Revenue Collection is Recorded Subject to Undercollection of Revenue	24 months
Contracted services: | Maximum
Disaggregation of Revenue [Line Items]
Period of Fixed Price Contracts to Operate and Maintain Water Systems at Various Military Bases	50 years
Contracted services: | American States Utility Services
Disaggregation of Revenue [Line Items]
Number of construction performance obligation | unit	1
Contracted services: | American States Utility Services | Maximum
Disaggregation of Revenue [Line Items]
Period of Fixed Price Contracts to Operate and Maintain Water Systems at Various Military Bases	50 years
Contracted services: | American States Utility Services | Minimum
Disaggregation of Revenue [Line Items]
Period of Fixed Price Contracts to Operate and Maintain Water Systems at Various Military Bases	15 years
Sales | Water: | GSWC | Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Percentage of total revenues	90.00%
Sales | Electric: | BVES | Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Percentage of total revenues	90.00%
Franchisor | Golden State Water Company and Bear Valley Electric Service, Inc.
Disaggregation of Revenue [Line Items]
Cost of services	$ 4,900	$ 4,000	$ 4,200